There has been used a hydraulic brake device that is employed in a brake device for vehicles. The hydraulic brake device includes a hydraulic cylinder that presses a friction pad against a brake disk to generate a braking force. Besides the hydraulic brake device, an electric brake device has been paid attention because of an introduction of a brake control system such as an ABS (antilock brake system), which electric brake device uses no hydraulic circuit.
The electric brake device includes an electric linear motion actuator wherein the rotational motion of an electric motor is converted into a linear motion of a linear moving member. The linear motion is used to press a friction pad against a brake disk to generate a braking force.
Such an electric brake device is disclosed in the below-identified Patent Document 1, for example. The electric brake device of Patent Document 1 includes an electric motor and a linear moving member integral with a friction pad that linearly moves between a standby position and a load applying position. The standby position is a place where the friction pad is spaced from the brake disk with a predetermined clearance between them, and the load applying position is a place where the friction pad contacts the brake pad and applies a load to the brake pad. The electric brake device also includes a motion converting mechanism that converts the rotational motion of the electric motor into a linear motion of the liner moving member. The device further includes a load sensor that detects the magnitude of a load that is applied to the brake disk through the friction pad. The electric motor is controlled by the load sensor on the basis of the magnitude of the load detected by the load sensor.